Continuous mining machine having a movable cutting head and movable conveying mechanism



Apurlil 9, 1957 F. A. LINDGRl-:N ETAL 2,788,201 TTING 11 Sheets-Sheet l CONTINUOUS MINING MACHINE HAVING A MOVABLE CU HEAD AND MOVABLE CONVEYING MECHANISM Original Filed Sept, 25, 1950 QSSEQ S wait@ www Amm,

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CONTINUOUS MINING MACHINE HAVING A MOVABLE CUTTING HEAD AND MOVABLE CNVEYING MECHANISM. Original Filed Sept.

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CONTINUOUS MINING MACHINE HAVING A MOVABLE CUTTING HEAD AND MOVABLE CONVEYING MECHANISM 'Original Filed Sept. 23. 1950 ll Sheets -Sheet 6 Telt fwlguzi INENTORS lli/m" chafa/flu APH] 9, 1957 F. A. LINDGREN ETAL 2,788,201

CONTINUOUS MINING MACHINE HAVING A MOVABLE CUTTING HEAD AND MOVABLE CONVEYING MECHANISM Originalilled Sept. 23, 1950 ll Sheets-Sheet 7 MAIN colvmoL SW/rll A zsz 264 MIN/v6 new forms 267 N j 260 261 -l f :L/ RH y M 0 L l PRESSURE ,4CH/.4 TED 5W! TC/l (jf/LOADING I( 183 FILME-'247 April 9, 1957 F. A. LINDGREN E'rAL 2,738,201

I CONTINUOUS MINING MACHINE HAVING A MOVABLE CUTTING HEAD AND MOVABLE CONVEYING MECHANISM #Trona/Ey April 9, 1957 F. A. UNDGREN ETAL 2,788,201 CONTINUOUS MINING MACHINE HAVING A MOVABLE CUTTING HEAD AND MOVABLE CONVEYING MECHANISM 11 Smets-sheet s Original Filed Sept. 23. 1950 RS frm ffl/lsf Pfclnooa BLE- FRAME Fna/vr SWING/Ns Secr/on 26 or 7A/N FRAME 4 April 9, 19.57 F A CONTINUOUS MIN'ING' M pglDGREN ETAL .2,788,201

h INE HAVING A MOVABLE CUTTING HEAD AND MOVABLE CONVEYING MECHANISM Original.k Filed Sept. 23. 1950 l1 Sheets-Sheet l0 l INVENTORS Original Filed Sept. 1950 April 9, 1957 F. A. LINDGREN ETAL 2,738,201

CONTINUOUS MINING MACHINE HAVING A MovABLE CUTTING HEAD ANUAMovABLE CONVEYING NEcHANIsN 11 Sheets-Sheet l1 lac/lard' (21m mist `,fl Tra/@NEW United States CONTINUOUS MINING MACHINE HAVING A MOVABLE CUTTING HEAD AN D MOVABLE CONVEYING MECHANISM Frank August Lindgren and Richard C. lLundqnist, Chin cago, Ill., assignors to Goodman Manufacturing Company, Chicago, Ill., a corporation of iiiinois Original application September 23, 1950, Serial No. 186,326, now Patent No. 2,695,700, dated November 30, 1954. Divided and this application May 1, 1953, Serial No. 352,86)

13 Claims. (Cl. 262ml?) This invention relates to mining, and particularly to improvements in low-height loading machines and contiuous mining machines for use in coal, salt and ore mines and the like.

This application is a division of our copending application Serial No. 186,326, filed September 23, 1950 for Mining Apparatus, now Patent No. 2,695,700.

One type of machine in which the present invention may be used to advantage is the continuous miner dis closed in the patent application of Frank Cartlidge, Serial No. 116,684, filed September 20, 1949, owned by the assignee of the present invention, now Patent No. 2,730,344. That machine has a cutter head which is operated tirst by sumping into the mine face followed by sumping downward to dislodge material from the mine face. The latter is transferred by gathering arms to an articulated conveyor which extends from a forward point adjacent the cutter head to the rear of the machine for discharging the material onto a receiver such as a shuttle car or belt conveyor.

During the above-mentioned sumping operation, the main frame of the machine remains stationary on its treads While a reciprocable auxiliary frame, which carries the cutter head is fed forward. During this forward feeding movement, it is important that the forward end of the conveyor and its associated gathering mechanism be maintained at a fixed distance from the cutter head for most ecient pick-up of the dislodged material.

Thus, the forward end of the conveyor must move back and forth with the cutter head. This would pose no problem in a high machine where the conveyor could be made in two sections including a nonreciprocable rear section, and a reciprocable front section, the sections being arranged in cascade relationship with the front discharging onto the rear through a hopper'. Where the machine must operate with very low headroom, as for instance in a 30-inch seam, the two-section cascade arrangement is distinctly disadvantageous because of the height it requires. For a low-height machine, therefore, a single articulated conveyor is preferred.

.A serious problem is posed in the use of a single articulated conveyor in that the rear end must remain fixed with respect to the shuttle car or other receiver while the front end must move back and fourth with extension and retraction of the cutter head as above-explained.l ln other words, the conveyor itself must stretch, or extend, and must operate as a conveyor while being extended or retracted. Herein lies an important problemwith which the present invention is concerned.

Accordingly, a principal Object of the present invention is the provision of extensible conveying apparatus for material handling apparatus such as the continuous mining machine described in the above-mentioned copending application.

Another important object of the invention is to provide a continuous mining machine of the type having a cutting or.. dislodging head mounted upona frame which is movable with respect to the main frame of the rna 'ice chine, and wherein the conveying mechanism is movableV with such movable frame so that the dislodged material is removed from proximity to the working face with optimum efciency.

Another object of the invention is the provision of a telescopical, conveyor-supporting means between stationary and extensible frames of a mining machine for supporting the conveyor in operative condition over its entire extensible range. Ancillary to this object is the provision of a gathering mechanism arranged at the forward end of the conveyor which is capable of automatically following up and down variations in the ground contour.

Figure 1 is a plan view of a continuous mining machine embodying a preferred form of the present invention;

Fig. 2 is a fragmentary side View, partly in section,

of the front end portion of the machine shown inl- Fig. l;

Fig. 3 is an exploded, fragmentary, perspective View of certain front end portions of the machine;

Fig. 3a is a fragmentary enlarged View of Fig. 3';

Fig. 3b is a plan view of the part shown in Fig. 3a;

Fig. tional front end of the conveyor and gathering mech-4 anism assembly, taken along line 4-4 of Fig. 3, and showing the gathering mechanism in its raised position, for tramming;

Fig. 4a is an enlarged view of a portion of Fig. 4;

Fig. 5 is a View similar to Fig. 4 butshowing the conveyor in extended position and the gathering mechanism in its ground-contacting position;

Fig. 6 is a view similar to Fig. 5 but showing the con-` veyor in its retracted position; i

Fig. 7 is a transverse cross section view of the gath ering and conveying mechanism as seen along line 7-7 of Figs. 2, 3 and 4;

v Fig. S is a diagrammatic view of one of the duplicate driving arrangements for the cutter head and gatheringl mechanism;

Fig. 9 is an enlarged cross sectional view of Fig. 5ik

taken along the line 9-9;

Fig. l0 is an enlarged fragmentary side elevationshowing how the gathering apron is mounted to the front end portion of the telescopical .conveyor supporting'.

means; Fig. 11 is a cross-sectional, plan view of Fig. 2, taken,

along the line lll-11 and showing the iluid-pressure-op-A of Fig. 11 taken along the line 15-15;

Fig. 16 is a cross sectional view of Figs. 1 and 2,

taken along the line 16-16;

Fig 17 is an enlarged longitudinal sectional view of Fig. 16 taken along the line 17-17;

Fig. 18 is a transverse cross sectional view of` Fig. 11

talten along the line 18-18;

Fig. 19 is a diagrammatic view of certain parts of the chain-tightening control mechanism;

Fig. 20 is a transverse sectional view taken along line .2d-Ztl of Fig. l;

Fig. 20a is a fragmentary longitudinal sectional View of Fig. 8, taken along line 20a-20a; and

Fig'. 21 is a fragmentary plan view of the machine-A showmg the cyhnder means utilized for extending and.

retracting the forward .portion 4 is an enlarged, fragmentary, longitudinal sec` General construction Referring now more specically to the drawings and particularly to Figures 1 and 2, the continuous mining machine shown comprises a portable, endless-treadmounted, main frame A having an auxiliary, reciprocable frame B mounted for forward and bacltward movement thereon. The reciprocable frame carries a cutting and dislodging head C which is pivotable from the ground level to the roof. The reciprocable frame carries gathering means D at the ground level which picks up mined material and transfers it to conveyor means E for discharge from the rear end of the machine.

The construction of the main frame A, auxiliary frame B, and cutting and dislodging head C are herein shown as being substantially identical to the construction of similar parts in the above-mentioned cfs-pending application, Serial No. 116,684, and hence they will not be described herein in detail.

In general, as shown in Figs. l and 2, the main frame A comprises: a center section 2i mounted on endless treads 22; a rear boom 23 pivotally mounted on the center section 2l for horizontal swinging movement about an axis 24 and for up and down tilting movement about another axis 25; and a iront, swinging section 26 pivotally mounted on the center section 21 for horizontal swinging movement about an axis Z7. The auxiliary frame B, above-mentioned, is carried on the front, swinging, section 26 of the main frame A and is mounted for forward and backward reciprocation thereon.

The auxiliary frame B carries a pair of main motors 28-28 for driving the head C and gathering means D. Suitable pi.ton and cylinder means 3th (Fig. 2l) is provided for moving the reciprocable frame B together with the motors 2S, mining head C, gathering means D and associated parts forward and backward on the front swinging section 26 of the main frame A, all as taught in the above-mentioned co-pending application Serial No. 116,684.

Brieily, as shown in Figs. 20 and 21, the piston and cylinder means 30 has at its forward end a piston rod 272 having an a e'rtured eyelet 273 which is attached by vertical pin 274 between ears 276 carried by the reciprocable frame B. At itsy rear, each of the cylinder means 30 is mounted on the swinging section 26 by means of a horizontal pin 277.

The mining headC is pivotable for up and down movement'v about a horizontal axis indicated at 29 in Figs. 1 and 2. A pair of double-acting cylinders 3l (Fig. 1), pivotally connectedk to a cross piece 32 on the cutter head C and having piston rods 33 pivotally connected to bifurcated extensions 34 of the reciprocable frame B, are suitably connected (by means not shown) to ahydraulic pressure generating pump 36 to raise and lower the mining head.

A double-acting cylinder 37 (Fig. l), pivotally mounted at 38 to. the main frame and having piston rod 39 pivotally mounted at 4l to an extension of the front swinging section 26, is elective to swing the latter and the reciprocable from B and cutter head C and other parts carriedthereby from right to left and from left to right when actuated by suitable hydraulic controls (not shown).

Gathering mechanism The description will now be directed more particularly to the novel elements of the invention residing in the gathering means D and extensible conveying means E.

As best shown in Fig. 3, the gathering means D comprises a shell-like apron 42 fabricated largely from sheet metal and mounted for up and down pivotal movement about a horizontal axis 7-7 (indicated at 43) on the reciprocable frame B. The apron 42 comprises a gene'rallyI U-shaped` at portion 44 terminating in a torward transverse "strengthening plate 4t?. -0n the bottom side of the plate 44 are welded a pair of spaced, longitudinally extending, vertical plates 47 defining between them a material-receiving channel 48. A downwardly inclined, substantially triangular plate 49 welded between the inner edges oi the legs of plate 44 and the vertical plates 47 function as upwardly extending, outwardly flared marginal portions of the channel 43 to facilitate feeding material into the latter. Between the plates 47, and rotatably mounted in bearing members 51, is a transverse shaft 52 carrying a forward, direction-changing roller for the conveying means E to be described in greater detail. Behind the roller 53 the gathering apron has a transverse horizontal supporting plate S4 welded between the vertical plates 47 and having a contour as best shown in Figs. 4, 5 and 6. The plate 54 functions as a riding or supporting surface for the upper reach of the conveying means. An inwardly extending guide rail S6, spaced above the plate S4 on each side of the latter, functions as a hold-down for the conveying means, all as will be described in more detail subsequently.

T he gathering mechanism D may be of any well known form but is herein shown as being an endless chain type including two laterally spaced endless chains 57, each guided in an orbital path about a driving sprocket 58 and a U-shaped shoe 59 about which are suitably secured upon the top surface of the apron plate i4 and along opposite sides of the receiving end of the conveying means E. These endless chains each have a plurality of spaced gathering arms 61 pivotally connected thereto and extending laterally therefrom and beyond the forward end of the apron 42 at their forward limit of travel to pick up loose material from the ground and discharge it into the channel i8 at the receiving end of the conveyor. Each of the sprockets 5S comprises driving means for its respective gathering chain and, as best shown in Figs. 3, 7 and S, each is mounted on a vertical shaft 62 carrying a beveled gear 63 and being driven by a pinion 64 which in turn is carried by a horizontal shat't 66 on beveled gear e7. Each vertical shaft o2 is suitably journaled in bearings 63 and 69 (Fig. 7) in a gear housing 71 which is mounted on the gathering apron by bolts 72 and 73.

Each of the gear housings 7i is provided` with a horizontal, transversely extending, exterior bearing portion 7d, concentric with the pivotal axis 43 on the gathering mechanism. Each of the bearing portions '74 functions as a trunnion for the gathering mechanism and is journaled for pivotal movement within a corresponding internal bearing or bore 76 (Figs. 3 and 7) formed within a gear housing 77 carried by the reciprocable trame B.

The gathering mechanism is pivotally movable up and down about its axis 43 by fluid-pressureoperated cylinder means including a cylinder '78 (Fig. 3) pivotally mounted at a point 79 on each side oi the reciprocable frame B. Each cylinder 76 has a piston rod 81 which is movable up and down responsive to pressure generated by a pump 271, to be described. A horizontal, forwardly extending lever S2 is pivotally mounted at its rear end to the piston rod di and 'at the other end it is fastened as a lever to a shaft S3 trunnoned in a bearing S5 on frame B. Each shaft extends inwardly and carries another level 9G. Each lever @tl is pivotally connected to a link 8o which.. as best shown in Fig. 7, is pivotally mounted on a pin dit' carried between a pair of rearwardly extending ears 8S mounted on the backside ot the upstanding rear arcuate guide portion 89 of the gathering apron. Thus, when fluid pressure is admitted. from a` suitable source to move the pieton rod-s 8l downward, the levers $2 willk be moved downwardly to rotate their corresponding shafts d3 and inner levers 90. They, in turn, will pull the rear end. of the gathering apron downward, through links 851i, to lift the front end of the gathering means to the position shown, for instance, in Fig. 5 where the gathering mechanism is clear of the floor, for tramr'ning.

it will be apparent that, 'since the gathering rr'tettnsl and thc cutter head C are both mounted on the recipro- Conveying mechanism The extensible conveying means, generally designated E, is herein shown as being of the laterally flexible, center strand, endless chain and flight conveyor type. lt includes an endless chain 91 (Fig. 1) formed from a plurality of aligned links which are vertically and horizontally pivoted at their opposite ends to front and rear portions of material carrying, transverse ights 92. The endless chain 91 passes around the previously mentioned direction-changing idler 53. At its rear end, the conveyor chain 91 is trained about another direction-changing idler 93 (Fig. 1) on the rear boom 23.

It will be apparent that when the forward idler roller 53 -is moved, by the reciprocable frame B, the distance spanned by the conveyor chain between the rollers :S3 and 93 will change. Important aspects of the present invention are to change the effective length of the chain automatically as the distance between the idlers changes and, to maintain a predetermined tension in the chain at all effective lengths.

Attention will now be directed to the improved means for supporting and tensioning the conveyor chain.

The main frame A includes upper horizontal plates 94 and 95 (Figs. 2 and 16) along which the upper reach 96 of the conveyor chain 91 runs. Hold-down angles 97 (Fig. 16), with inner wear plates 98, maintain the ights 92 in working proximity with the top surface of plate 94. The lower reach 99 of the conveyor chain runs along below the underside of plates 94 and 95, being supported by conventional means including plate 100. The upper and lower reaches of the conveyor chain are supported in like manner on upper and lower plates 105 and 105g on the rear boom 23.

The upper and lower reaches of the chain at the juncture between the rear boom and main frame A may be flexibly supported for turning displacement about vertical pivot 24 in any suitable manner, as for instance between side plates 101 (Fig. l) in the manner taught in the above-mentioned co-pending patent application, Serial No. 116,684.

Forwardly of the conveyor-supporting plates 94 and 95 on the main frame A, the upper and lower reaches of the conveyor chain are ilexibly supported for turning movemnet about pivot 27, in this case by a structure including series of inter-connected, overlapping vertebrate plates 102 made in accordance with the teaching of Patent No. 2,208,269 granted July 16, 1940, to Frank Cartlidge.

Forwardly of the vertebrate elements the swinging section 26 is provided with vertical side plates 103 (Fig. 4) dening a trough for the conveyor chain and is provided with top and bottom horizontal plates 104 and 106 for supporting the upper and lower reaches 96 and 97 of the conveyor chain respectively.

- Further forwardly, ahead of the plates 104 and 106, is adownwardly inclined, telescopical, conveyor-supporting frame, generally designated 107 which comprises two inter-engaging box sections 108 and 109. Section 108 is formed with upper and lower 4lioor plates 111 and 112 connected at the sides by walls 113 (Figs. 4 and 9), the latter having upwardly and outwardly extending side wall portions 114-114:1 to match similarly flaring trough-like side walls 116 and 117 (Figs. 1 and 2) on the swinging and vertebrate sections 26 and 102, respectively. As shown in Figs. 3 and 4, the oor 112 is provided on each side, at the rear end, with an ear 118 having a transverse aperture therethrough. The swinging section 26 is provided with a pair of mating forward extensions 119 carrying transverse pivot pins 121 on which the aperture-carrying ears 113 of the box section 10S are pivotally mounted. In order to provide for up-and-down pivotal movementV of section 108 while maintaining the engagement between the upper door plates 111 and 104, the latter are formed with mating cylindrical surfaces 122 and 123 which are generated by striking arcs about the axis of pivot pins 121. This may best be seen by reference to the enlarged fragmentary view shown in Fig. 4a.

The transverse configuration of box section 109 is best shown in Fig. 9. It will be observed that it is formed with upper and lower floor plates 124 and 126 which overlie and underlie floor plates 111 and 112 respectively of the inner section 108. Each side of upper plate 124 is bounded by a vertical wall 127 terminating in an outwardly tiered trough-like wall 127e which closely follows the shape of the corresponding walls 114 and 114:1. Similarly, each of the floor plates 126 is bounded by opstanding and outwardly ared side walls 128 and 128a which are shaped like corresponding side walls 114 and 11411 respectively. Each corresponding pair of wall sections 12M-123e is joined at the top by a bridging section 129.

Thus, as shown in Fig. 9, the cross sections of parts 108 and 109 are such that the formerl fits telescopically inside the latter for movement between an elongated condition as shown in Fig. 5 and a retracted condition as shown in Fig. 6.

At its forward end, as shown in Fig. 3a, the floor plate 126 is narrowed somewhat by a cutout 131 on each side. The resulting, slightly narrowed forward portion 132 of the door plate 126 is formed with an upwardly inclined lip 133 adapted to overlie and. follow the rearwardly extending arcuate lip 134 of floor plate 136 in the gathering apron d2 (see Figs. 5 and 10). Upstanding along each side of the narrowed floor plate portion 132 and welded thereto is a vertical side section 137, the rear part of which abuts an upper, forward part of wall section 127, as shown in Fig. 3a. An upwardly and out; wardly inclined flare 138, comprising segments 139 and 141, and shaped along its upper periphery like a flattened Z, is mounted along each forward end of the telescopic section 109 as follows: As shown in Fig. 3a, the segment 139 is butt-welded to the end' of wall 127a and buttwelded to the top edge of vertical section 137, segment 141 being butt-welded to the forward edge of segment 139. As will be pointed out in detail subsequently, the dares 13S function as outerlaps for the upper spaces which otherwise would exist between the ytelescopical section 109 and the apron d2, thereby preventing spillage of material being carried by the conveyor chain at all conditions of up and down articulation.

As shown in Fig. 3a, on each side of the telescopical section 109, the upper edge of plate 137 and the adjacent lower edge of segment 141 is formed to define a forwardly extending curved slot 142 into which is fitted a forwardly-extending lug having an aperture 145. The lug 140 is mounted as by welding to a reinforcing boss which itself is welded to plate 137. As will be seen, the lugs 140 cooperate with ears 143 at the rear of the gathering apron to hinge the apron to the box section 109. Each ear 143 is mounted by means of a lap-weld along a line 144 (see Figs. 10 and 13). This offsets each ear member 143 outwardly relative to the corresponding apron side wall 47 and conveniently provides a recess 146 within which the corresponding side wall 137 may operate. Further, this arrangement provides for the inner surfaces 147, 14S and 149 (Fig. 13) of side plates 47, 137 and 113, respectively, to be substantially in alignment whereby, in turn, to provide substantially uniform trough width for the conveyor chain. As shown in Fig. 3, the ear member 143 and the adjacent portion of the apron side wall 47 are formed with circular openings 151 and 1S1a respectively.

Along each outer side of vertical wall 137 (see Fig. 3a) the boss 150 serves to space outward, a convenient distance, the lug 140 which is attached to it. This leaves a space 152 (Fig. 3b) at each side forreceptlon of the cor 2' responding ear 1,43 of the gathering apron. Each lug is provided with a pair of drilled and ltapped holes 154 and the Vtrarrsy-erse bore 145 approximates the diameter of openings 151--151a in ears 1.43. To assemble the apron 42 into hinged relationship with the telescopical 109, the parts are brought together to the position shown in Figs. 3b and l0, with the lug 140 overlapping the ear member 143 on each side, and with lug openings 145 and ear openings fidi- 15M in alignment. The parts are then fastened together by inserting a pin 157 (Fig. 3a) through each corresponding set of openings 145K-151-151m Each pin 157' is then held in place by a locking plate S to which it is attached, the locking plate being retained by cap screws 159 extending through l its holes 161 and being threadably engaged withY the tapped holes 154 in lug 140.

AThe pivot pins 157 are located on a center, as shown in Fig, l0, which lies inthe plane of the upper flight which runs between the oor plates 54-124 and guide rails 56--162 which are in the apron d2 and telescopic section 109, vrespectively.

Cooperative relationship between gather/zg and conveying arrangements Figs. 5 and 6 illustrate the action of the telescopical sections and the pivotal joints just described. As previously stated, the reciprocable frame B carries the gathering apron 42 for forward and backward movement, the gathering apron being pivotal about the transverse axis indicated (in Fig. 3) at 43 in the center of gear housing 77'. When the reciprocable frame B is extended, forwardly, the telescopical assembly lil? will be extended. This will cause section 108 to pivot upwardly about pin 121. At the same time, the telescopical section 1t9 will be pulled forwardly by the apron 42 by means of force exerted through the hinge pins 157. Likewise, as the apron is drawn forward, the telescopic section 199 will be rotated counter-clockwise (Fig. 6) about the hinge pins 157 while the angle between the conveyor supporting plates in the apron and in section 109 becomes flatter, as they approach the fully extended condition shown in Fig. 5,. It will be apparent that, as the reciprocable frame B moves the gathering apron 42 forward and backward, the latter is free to follow, flexibly, any irregularities in the oor by reason of the exible structure just described. Por instance, as the ground-contacting shoe d6 enters a depression, the apron d2 simply rotates clockwise about axis t3 a suitable amount accompanied by compensating pivotal movements about pins 121 and 157 and cornpensating telescopic adjustment between the individual conveyor supporting sections 108 and 109.

Conveyor chain tensioning and storing means Referring now to the fluid-pressure actuated chain tightening means, generally designated i639 in Fig. 12, which comprises one of the important features of the present invention, it is supported by the vertical side members 164 (Fig. 16) of the main frame. Attached, as by welding to the inner surface of each side member 164, are upper and lower horizontally extending angles 165 and 1.67, respectively. The angles are provided with notches 168 and 1,69, respectively, within which upper and lower ears 171 and 1.72 of Vertical plate sections 173 are n terloclgably engaged. At the bottom ot each plate section and as vattached by means of welding along the line 174 is a short horizontal plate section 176. A cylinn der block 177 is provided with transverse lugs 178 which rest atop the horizontal plate sections 176 and are xed thereto by means of bolts 179. Thus, it will be seen that the cylinder block 177 is restricted against both longitudinalandtransverse displacements relative to the trarne `throug'gh the interengagement of ears 171 and 172 within "e essies 168 and1t9. At the same time this arrangement lli permits the cylinder block 177 -to be removed readily simply by vunfastening bolts 179.

As best shown in Fig. 11, the cylinder block 177 is formed with four cylinder bores 181, 181e, 182 and 182e; 181 and 181e: may, for convenience, be referred to as outer cylinders and 182 and 182er as inner cylinders. Each cylinder is provided at its head end with suitable cap or closure means 133. Opposite the closure means in each case is a suitable packing arrangement 184 for providing a iiuid ti-ght seal about a corresponding one of the piston rods 136, 186e, 187 and 18711. Within each bore, a piston 188 is connected to the inner end of the corresponding piston rod.

The interior or the cylinder block 177 is suitably provided with ports and passages (not shown) which concurrently connect the head ends of all cylinder bores with au exterior pressure conduit 189. By this arrange-` ment, when fluid under pressure is directed into the conduit 189 it can be effective to extend all four piston rods.

Each end of the tensioning means 163 is provided with a longitudinally reclprocable pressure block 191 having a hat inner surface 192 against which the lcorresponding pair of piston rods abut. Each block 191 has a'pair of ears 19?: through which a transverse cross shaft 194 is mounted. Between each pair of ears 193, an idler roller E is retained. for rotation about the shaft 194. In prac tice, suitable journal bearings would be employed but are not shown here in order to simplify the disclosure. To prevent the pressure blocks 191 from cooking when force ap alied to them by the piston rods, they are guided b the following arrangement:

Referring to Fig. l2, each end of each cross shaft 194 carries a cylindrical bushing 197 fixed thereto by a pin 198. Mounted on the outer end of each bushing 197, as by welding at 19?, is one of the longitudinally extending guide strips Zilla, Ztllb, 2h10 and 201e'. A gusset 202 is attached, as by welding, along lines 203 and 204 to each corresponding pair ot the above-mentioned guide strips and bushings. A short, longitudinally extending member 205 is welded along one side or the other of each of the gussets 2&2 tor additional strength. A locking member Ztl? is aliixed by means ol' a bolt 239 to each ad,-l jacent gusset 202 and extends into an end slot in one end of each pressure block 192 and functions to lock the latter against rotation about its shaft 19d. Thus, to remove, any particular one o the guide strips, it is necessary onlyto remove the corresponding pin 19d. The bottom guide strips 291e and Zilli!) are guided along their lower edges 2%9 by engagement with the top surfaces 2.1i of the angle members 167. Similarly, the top guides 201e and 29M are guided along their upper edges 212 by engagement with the under surfaces 213 of the angle members 166. Also, upper and lower pairs of said guide strips are slideable against one another along a common inner face designated 214 in Fig. l2.

` As best shown in Fig. 2, the lower reach of the conveyor chain is looped about a drive sprocket 2.16, a roller 217 and the two idler rollers 196 to dispose it in the form of an expandable loop which may be expanded to store chain responsive to pressure directed into the block 177 through conduit 159.

With the structure just described, it will be seen that, when the reciprocaole frame B is moved forward', relative to the main frame to extend the conveyor chain by .in-` creasing the distance between front and rear idlers Sli and 9,3, the hydraulic loop 153 will be contracted, against the pressure within the cylinders, to thereby permitthe proper length ot' chain to be drawn out. The hydraulic pressure, being effective while the chain is being drawn out, will maintain the latter at all times at a predesired tension as determined by the pressure of iluid in the bl c; t7?. Similarly, when proper pressure is applied through conduit 189 while the `'auxiliaryframe B is being; retracted, the pistonY rods will press the rollers 196 apart a corresponding amount to automatically store the excess chain inthe pressure loop.

Motor drives v The conveyor driving sprocket 216 (Fig. 2) is rotatably driven by a motor 218 (Fig. l) through a speed reducer 219, including a worm 221 and a worm wheel 222 as shown in Fig. 16), a friction clutch 223, and certain other gearing and parts shown in detail in the above-mentioned co-pending application, Serial No. 116,684.

As will now be described, the main motors 28 drive both the cutter head C and the gathering mechanism D.

The gear train through which the two motors cooperate, simultaneously, to rotatably drive the cutter chains 224 (Fig. l) and drum 226 (Fig. l) of the cutter head is described in detail in the above-mentioned co-pending application, Serial No. 116,684. That part of the driving arrangement, whereby each of the motors 28 drives one of the gathering chains 57, is diagrammatically shown in Fig. 8 where it will be seen that the motor shaft 227 carries a pinion 228 which drives an. internally toothed ring gear 229 which in turn rotatably drives a longitudinal shaft 231 carrying a sprocket 232 about which is trained a chain 23d. At a lower level (see also Fig. 20a), and driven by a chain 23d, is another sprocket 236 which drives a forwardly extending shaft 237 through frictional clutch means 238. A beveled pinion 239 carried by shaft 237 engages with and drives beveled gear 67, which, as previously described, drives one of the chains 57 through shaft 66. By this arrangement it will be seen that, because the pivotal axis d3 (Figs. 4, 5 and 6) of the gathering apron d2 coincides with the axes of the two transverse stub shafts 66, the apron may be pivoted up and down rreely at all times. Thus, even under conditions where the shafts 66 may be locked against rotation, gears 63 would simply turn suiciently to accommodate pivoting of the apron.

Motor controls lt will be apparent that if the conveyor chain 91 is slack at the time the conveying motor 21S is started, or becomes so while running, it may disengage from the driving sprocket and cause damage. To prevent such an occurence, another feature of the present invention includes control means for conditioning the conveyor driving motor 218 for operation only While a predetermined tension is applied to the chain by the pressure loop 163. This control means is shown diagrammatically in Fig. 19 where the conduit 189 directs output from pump 36 into the cylinder block 177. A conventional unloading valve 247 is provided for bypassing uid through conduits 248 and 249 to a tank 251 when the output pressure attains a predetermined maximum. An electrical motor 253 is coupled to drive the pump means 36 and is connected, by lines 251i and 256, to E. M. F. sources L1 and La, through a switch 252.

A normally-open, pressure-responsive switch 257 has a pressure-responsive piston element 258 communicating through conduit 259 with conduit 189, for) closing of contact 261 by conductor bar 262 responsiveto pressure applied to the cylinder block 177. The pressure at which the switch is closed is dependent on the resistance of compression spring 263. In practice, the switch may be constructed to close at any one of a range of pressures.

Now considering the electrical part of the circuit, which is conditionable for energization by pressure switch 257, lines 264 and 266 are connected respectively with the E. M. F. source L1 and L2. A manually operable control switch 267 is connected in series with pressure switch 257 in line 266. In order to provide for concurrent operation of the cutter head C, the gathering mechanism D and the chain conveyor 91, the main driving motors 28-28 and the conveyor motor 218 are connected in parallel with one another and in series with switches 257 and 267, as shown. z'

. As a representative set of conditions, assume lt-has been found by experiment that a pressure of at least 200 pounds per `square inch need be applied to the cylinder block 177 to maintain the conveyor chain 91 under suitable tension under all operating conditions. The pressure-actuated switch 257 will be selected, or set, to close contacts 261-261 only at pressures above, say 210 pounds per square inch. The unloading valve means 247 will be set to unload at some higher value, say, 225 pounds per square inch.

With the :above settings, assume an operator wants to start the machine. lf he closes switch 267, nothing happens, because the Lr-La circuit is open at switch 257 due to the fact that there is no pressure in conduit 189, On the other hand, if the operator first closes the main control switch 252, to start motor 253, to in turn cause the pump means 36 to bring conduit 189 up to the 200 pounds per square inch setting of pressure switch 257, the latter will be closed, thereby conditioning the circuit for euergization of motors 28h28 and 218 whenever con trol switch 267 is subsequently closed.

lf, during operation, the pressure in line 189 drops below the 200 pound per square inch safety point, as for instance by failure of pump means 36, the pressure switch will open, automatically stopping theV conveyor motor 218 (as well as motors Ztl- 28). This arrangement eectively guards against damage which would result ifidriving of the chain were attempted with insuilcient tension.

Operation Considering now the overall operation of the machine,V

refer first to the plan view of the entire machine as shown in Fig. l. Assume, for example, that the machine is at rest after having previously defined a room or passage in a coal seam having side walls 268 and a spherical end wall 269. To start the machine at the beginning ofa shift the operator first closes main control switch 252 (Fig. 19) to start the pump motor 253. This operates the previously described pump 36 as well as another pump 271 which supplies pressure for the cutter head lifting cylinders 31, the front swinging cylinder 37, the auxiliary frame reciprocating `cylinders 30, the gathering apron lifting cylinders 78 and the rear boom lifting end swinging cylinders'(not shown).

As soon as the pump 36 brings the pressure up in conduit 189 to a value suicient to close pressure switch 257, main driving motors 28-28 and conveyor motor 218 can be started by the operator by closing switch 267. This will start the cutter chains 224 (Fig. l) and the cutter drum 226 of the head C rotating in a cutting direction; at the same time, it will start the gathering chains 57 (Fig. 8) moving in their orbital paths to remove from the licor any coal dislodged by the cutter head; and likewise, the upper reach of the conveyor chain will be started moving backward to discharge coal ofi the rear end of the discharge boom 23 into a waiting shuttlecar, conveyor belt or the like. l

To start a cut, the operator turns the swinging-frame section 26 to one side of the room, `asshown-in broken lines in Fig. l. This is carried out by admitting pressure, through suitable controls (not shown), to the swinging cylinder 37.

By releasing pressure from the cylinder 78 (by'control means not specifically shown), the operator will drop gathering apron into contact with the ground. Then he is ready to mine. f

To mine, coal for instance, with this machine, :the

cutter head is tilted about its axis 29, upward to the roof,-

by directing pressure into cylinders 31. -Then, with the gathering apron against the ground, the auxiliary frame B is advanced by directing pressure into reciprocating pistons 30 (Fig. 20) to sump the cutting headinto the mine face 269 adjacent the roof. During sumping the gathering apron 42 will be moved with the head C and will follow any irregularity in the oor by adjustably. pivotingA about the axis 43. As theqreciprocable frame,

is" @nov-ed forward the effective length oft-he conveyor, as ydetermined by the spacing between forward idler 53 :and the rear idler 93, will be increased while 'the length of the pressure loop 163 correspondingly decreases to feed out the necessary extra chain. (An important aspect of the present invention is that, because the pressure loop 16S-'is tensioned by lluid pressure, which is constant, the tension in the chain will remain the same at all conditions of expansion or contraction.) When the cutter :head is sumped in a -desired amount, say 18 inches or so, the operator will admit pressure to cylinders 3l to swing the cutter head downward, ripping coal oli the face to be picked up by the gathering arms for transfer to the rear of the machine by the gathering and conveying mechanisms D and E.

The above-mentioned sumping and ripping operations will be repeated at a'series of locations across the face until a new face 270 is defined following which the machine will be moved forward and the steps repeated.

Thus, it will be seen that the mechanism described above and covered by the following claims is primarily useful in continuous miners, but possesses little or no substantial utility in loading machines.

While one form in which the present invention may be embodied has been shown and described it will be understood that various modifications and variations thereof may be effective without departing from the spirit and scope of the invention as defined by the appended claims.

' We claim:

l. Extensible conveying apparatus for a mining machine comprising: portable frame means; an auxiliary frame mounted for reciprocable movement relative to said frame means; an extensible support pivoted to said frame means; an endless conveyor trained for orbital movement about said frame means and said extensible apport; said extensible support having, remote from the pivotpoint, a portion carried by said auxiliary frame for extending and retracting said support and moving that portion of the conveyor member carried thereby upon rcciprocation of said auxiliary frame relative to the frame means.; and means carried by the frame means edective to compensate for the movement of the portion of the conveyor member on the support upon extension and retraction of the latter.

2. Extensible conveying apparatus for a mining machine comprising: portable frame means; an auxiliary frame mounted for reciprocaole movement relative to said frame means; an extensible support; an endless conveyor trained for orbital movement about said frame means and said extensible support; said support including a pair of tclescopical sections, one pivoted to said frame means, and the other pivoted to said auxiliary frame; said support being concurrently extensible and pivotable about its connections with the frame means and the auxiliary frame upon movement of the auxiliary frame relative to the frame means; and means carried by the frame means for compensating for expansion of that portion ofthe conveyor on said support upon extension ofk the latter.

3. Extensible conveying apparatus for :a mining ma chine comprising: portable frame means; an auxiliary frame mounted for reciprocable movement relative to said trame means; an endless flexible conveyor member trained for orbital movement about said frame means; an 'extensible support about which said tlexible conveyor member is trained for orbital movement; said support including a pair of telescopieally assembled sections, a tirst section being pivoted to Said frame means, and a second section having means associated therewith for pivoting it with respect to the auxiliary frame whereby movement of the latter relative to said frame means is concurrently eiec-tiye to vary the length of the support l 'tprn kthe latter about its pivotal connections witlrf sair'frame incansan'df auxiliary frame; a groundngag.'

ing .gathering apron pivotally mounted on said auxiliary frame proximate said second section for independent pivotal movement to followirregularities in the ground and gather material therefrom and transfer it to said conveyor member; and means carried by the frame means for compensating lfor change in length of that portion of the conveyor member trained about the support on change in length `of the latter.

4. `Extensible conveying apparatus for a mining machine comprising: portable frame means; an auxiliary frame mounted for reciprocable movement relative to said frame means; an endless, flexible, extensible conveyor assembly trained for orbital movement about said frame means; supporting means for said conveyor member including upper and lower telescopically assembled sections; said upper section being pivotally mounted on vsaid frame means and normally disposed to guide conveying and return reaches of said conveyor member at an angle relative to the horizontal; said lower section being pivotally mounted with respect to said auxiliary frame and likewise disposed to guide conveying and return reaches of said conveyor member; said auxiliary frame carrying ground-engaging gathering means which is pivotable relative thereto and the following variations in floor level; said gathering means carrying an extension of said conveyor member disposed at a lesser angle relative to the horizontal than the first-mentioned angle when the gathering means is engaged with the ground whereby to dispose said conveyor in close proximity with the material receiving portion of said gathering means so as to transfer material from the ground to the conveyor member most effectively.

5. Extensible conveying apparatus for a mining machine comprising: portable frame means having a reciprocable frame mounted for forward and backward movement thereon; gathering vmeans including a groundengaging apron carried forward and backward by said reciprocable frame and mounted for up and down move- .ment relative to the reciprocable frame to follow variations in the oor level; an extensible support having one portion pivotally mounted on said frame means and another portion pivotally mounted relative to said reciprocable frame; direction-changing means for a conveyor member carried within said gathering apron; an endless flexible conveyor member trained for orbital movement along said frame means and extensible support and about said direction-changing member to carry away material picked up by said gathering means; and means associated with said conveyor member for compensating for expansion of that portion of the conveyor member on said support upon expansion of the latter; whereby upon forward movement of said reciprocable frame, said support will concurrently extend and pivot relative to said frame means and said reciprocable frame to correspondingly re-orient said flexible member to follow such movement of the reciprocable frame.

6v. Extensible conveying apparatus for a mining machine comprising-r portable frame means; an auxiliary frame mounted for; reciprocable movement relative to said frame, means; an extensible support pivotally connected to saidv portable trarne means; an endless llexible conveyor member trained for orbital movement about said frame4 means and said extensible support; said support including apair of telescoping sections; one of said telescoping sections beingk pivoted to said, auxiliary frame.; said support beingconcurrently. extensible and pivotable about itsfconnections'with said portable frame means and said auxiliaryr frame upon movement of said auxiliary frame relative to said portable frame means; said exten sible support having spaced plates for guiding the conveying and return reaches of said conveyor and means carried by said portable frame means for compensating forY expansion*` of that portion of the conveyor member on said support upon extension of the latter. r -TtExt'ensible conveying" apparatus for` a mining machine comprising: portable frame means, an auxiliary frame mounted for reciprocable movement relative to said frame means; an extensible support pivotally connected to said portable frame means; an endless ilexible conevyor member trained for orbital movement about said frame means and said extensible support; said support including a pair of telescoping sections; one of said telescoping sections being pivoted to said auxiliary frame; said support being concurrently extensible and pivotable about its connection with said portable frame means and said auxiliary frame upon movement of said auxiliary frame relative to said portable frame means; and means carried by said portable frame means for compensating for expansion of that portion of the conveyormember on said support upon extension of the latter.

8. A machine for mining coal or the like comprising in combination: a main frame, an auxiliary frame reciprocably movable with respect to said main frame and having cutting means disposed thereon, an extensible support pivotally connected to said main frame, an endless conveyor trained for orbital movement about said main frame and said extensible support, said extensible support having `a pair of telescoping sections, one of which is pivoted to the main frame, and means affording a connection between the other of said telescoping sections and said auxiliary frame, so that said endless conveyor is in position with respect to said cutting means to receive cuttings for all positions of said auxiliary frame.

9. A machine for mining coal or the like comprising in combination: a main frame, an auxiliary frame reciprocably movable with respect to said main frame and having cutting means disposed thereon, an extensible support pivotally connected to said main frame, an endless conveyor trained for orbital movement about said main frame and said extensible support, said extensible support having a pair of telescoping sections, one of which is pivoted to said main frame, gathering means disposed at the end of the other of said telescoping sections and means affording a connection between the other of said telescoping sections and said auxiliary frame, so that said gathering means is in position with respect to said cutting means to receive cuttings for all positions of said auidliary frame.

10. A machine for mining coal or the like comprising in combination: a main frame, an auxiliary frame reciprocably movable with respect to said main frame and having cutting means disposed thereon, an extensible support pivotally connected to said main frame, an endless conveyor trained for orbital movement about said main frame and said extensible support, said extensible support having a pair of telescoping sections, one of which is pivoted to said main frame, gathering means disposed at the end of the other of said telescoping sections, and means affording a connection between the other of said telescoping sections and said auxiliary frame, so that said gathering means and said endless conveyor will be moved into position with respect to said cutting means to receive cuttings for all positions of said auxiliary frame.

11. A machine for mining coal or the like comprising in combination: a main frame, an auxiliary frame reciprocably movable with respect to said main frame and having cutting means disposed thereon, an extensible support pivotally connected to said main frame, an endless conveyor trained for orbital movement about said main frame and said extensible support, said extensible support having a pair of telescoping sections, one of which is pivoted to said main frame, means affording a connection between the other of said telescoping scctions and said auxiliary frame, so that said endless conveyor will be moved into position with respect to said cutting means to receive cuttings for all positions of said auxiliary frame, and means for compensating for the change in length of the material carrying reach of said endless conveyor by movement of said auxiliary frame.

12. A machine for mining coal or the like comprising in combination: a main frame, an auxiliary frame reciprocably movable with respect to said main frame and having cutting means disposed thereon, an extensible support pivotally connected to said main frame, one endless conveyor trained for orbital movement about said main frame and said extensible support, said extensible support having a pair of telescoping sections, one of which is pivoted to said main frame, gathering means disposed on the other of said telescoping sections, means aiording a connection between the other of said telescoping sections and said auxiliary frame, so that said gathering means and said endless conveyor are in posi tion with respect to said cutting means to receive cuttings for all positions of said auxiliary frame, and means for compensating for the change in length of the material carrying reach of said endless conveyor by movement of said auxiliary frame.

13. Extensible conveying apparatus for a mining machine comprising: portable frame means; an auxiliary frame mounted for reciprocable movement relative to said frame means, an extensible support comprising telescopic members, one of the telescopic members being connected to the frame means and another of the telescopic members being connected to the auxiliary frame, an endless flexible conveyor member trained for orbital movement between said frame means and said auxiliary frame, the material-carrying run of said conveyor member being trained across said telescopic members for support throughout a range of relative movement of said members corresponding to a range of reciprocable movement of said auxiliary frame, and means carried by said portable frame means for compensating for change of length of that portion of the conveyor member on said support upon change of length of the latter.

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